Over the past years, our research on baobabs mainly focused on the largest Malagasy species, namely the Reniala or Grandidier baobab (Adansonia grandidieri Baill.). The biggest A. grandidieri are located in the Morombe area, especially in the so-called Andombiry Forest. This giant forest of Reniala hosts well over 6000 mature individuals, out of which more than 30 have very large sizes, i.e., circumferences over 20 m. We investigated, measured and dated by AMS radiocarbon the largest specimens. We found that all large Grandidier baobabs are multi-stemmed. They mostly exhibit a closed ring-shaped structure, with a false cavity inside. In this architecture, which enables Grandidier baobabs to reach very large sizes, the stems that build the ring typically have similar ages. Here we present the AMS radiocarbon investigation of two large baobabs, A 215 (girth 21.50 m) and A 257 (girth 25.70 m). According to dating results, the baobab A 215 has an age of only 375 years. It consists of four fused stems and has a closed ring-shaped structure. The baobab A 257 has the second largest trunk of all known live Reniala trees. It also exhibits a closed ring-shaped structure, with five fused stems around a false cavity, which has an opening toward the exterior. The dating results indicate that A 257 is around 900 years old.

中文翻译：

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马达加斯加 Andombiry 森林中最高级 Adansonia grandidieri 的建筑和年代调查

过去几年，我们对猴面包树的研究主要集中在最大的马达加斯加物种，即 Reniala 或 Grandidier 猴面包树（Adansonia grandidieri Baill.）。最大的A. grandidieri位于 Morombe 地区，尤其是在所谓的 Andombiry 森林中。这个巨大的 Reniala 森林拥有超过 6000 只成熟个体，其中 30 多个具有非常大的体型，即周长超过 20 m。我们通过 AMS 放射性碳对最大的标本进行了调查、测量和测年。我们发现所有大型 Grandidier 猴面包树都是多茎的。它们大多表现出封闭的环形结构，内部有一个假腔。在这种架构中，Grandidier 猴面包树能够达到非常大的尺寸，构建戒指的茎通常具有相似的年龄。在这里，我们展示了两个大型猴面包树的 AMS 放射性碳调查，A 215（周长 21.50 m）和 A 257（周长 25.70 m）。根据测年结果，猴面包树A 215的年龄只有375岁。它由四个融合的茎组成，具有封闭的环形结构。猴面包树 A 257 的树干在所有已知的活 Reniala 树中排名第二。它还呈现出一个封闭的环形结构，在一个假腔周围有五个融合的茎，假腔有一个向外的开口。测年结果表明 A 257 大约有 900 年的历史。